Sprocket For Easy Cleaning

ABSTRACT

A drive sprocket for driving a modular belt having a plurality of belt modules with intercalated link ends connected by transverse pivot members to form hinges. The belt modules may have transverse ribs. The drive sprocket is driven by a shaft. The drive sprocket has a central opening for receiving the shaft. The body has a plurality of teeth disposed in pairs along a periphery of the body. The body has a first opening formed between adjacent pairs of teeth and extending toward the center of the sprocket to provide access to the hinge area, when the belt engages with the sprocket, for application of cleaning fluid.

FIELD OF THE INVENTION

The present invention relates to modular conveying apparatus.

BACKGROUND OF THE INVENTION

Sprockets for driving modular belts are usually made from stainlesssteel or plastic that is machined or molded. In food processingapplications, sprocket drives are a particularly critical area forcleaning. It is important to be able to periodically remove the residualmatters totally from the sprockets and on the rear side of the belt, inorder to avoid bacteria growth and spoilage of the food processed on thebelt. For this purpose sprockets have been designed with large openingsto allow cleaning fluid to pass from the side and reach the criticalareas to be cleaned. Such sprockets are disclosed in U.S. Pat. No. Re.38,607. Typically, the sprocket rim and teeth are covering the hingesand hinder the fluid from reaching the hinge area for proper cleaning.Therefore the sprocket disclosed in the patent further provides pairs ofteeth in a double row such that the teeth of a pair are offset. Thisarrangement allows better cleaning access to the rear belt side andeasier release of residual matters collected on the rear belt side. Butthis design is only partially solving the problem since the criticalhinge areas are still covered by the sprocket rim to a certain extent,when engaged on the sprocket. Therefore good access to these hinges isof primary importance.

U.S. Patent Publication No. 2004/0222072 proposes to solve this problemby using a sprocket with an oblique shape as illustrated in FIGS. 3A, 3Bof the publication. With this design, the teeth will laterally changetheir position on the rear side of the belt and regularly expose anotherplace on the belt for better cleaning access. Although this is improvingcleanability, the proposed solution is still having the shortcoming ofperiodically covering the hinge completely in a certain position.Another typical feature of the disclosed sprocket is the tracking on thebelt by additional teeth engaging in the hinge gaps (FIG. 3B, referenceno. 74). During sprocket engagement these teeth enter into the hinge gapbetween two links and thus push residual matter into this gap, making itagain difficult to clean. Also, the drive pockets (reference 72 as shownin FIG. 3A of the publication) of the sprocket are engaging closely overthe drive faces which are identical with the center cross bar on therear side of the belt. The drive surfaces totally covered by theenclosing drive pocket are another place where residuals are physicallysqueezed in between thus making cleaning more difficult.

Another patent proposing a similar solution is U.S. Pat. No. 6,740,172.The patent does not disclose the drive engagement but disclosessectional sprockets used to laterally shift the engagement areaperiodically. Accordingly, there is a need for an improved sprocket foreasy cleaning that avoids the above described shortcomings.

SUMMARY OF THE INVENTION

The present invention meets the above described need by providing adrive sprocket for driving a modular belt having a plurality of beltmodules with intercalated link ends connected by transverse pivotmembers to form hinges. The belt modules may have transverse ribs. Thedrive sprocket is driven by a shaft. The drive sprocket has a centralopening for receiving the shaft. The body has a plurality of teethdisposed in pairs along a periphery of the body. The body has a firstopening formed between adjacent pairs of teeth and extending toward thecenter of the sprocket to provide access to the hinge area, when thebelt engages with the sprocket, for application of cleaning fluid.

The sprocket may also be provided with a curved recessed portionadjacent to the first opening. A plurality of second openings may bedisposed in the body of the sprocket between the central opening and thefirst opening.

The pairs of teeth may be arranged in offset fashion with respect to acentral axis or the teeth may extend for the entire with of thesprocket.

A cleaning system may be arranged proximate to the sprockets such thatcleaning fluids are sprayed through the curved recessed portion into theopening disposed adjacent to the hinge of the belt when the belt engageswith the sprocket. The cleaning system may include a manifold incombination with spray heads pointed toward the sprocket.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated in the drawings in which like referencecharacters designate the same or similar parts throughout the figures ofwhich:

FIG. 1 is a side elevational view of a sprocket according to a firstembodiment of the present invention;

FIG. 2 is an end elevational view of the sprocket shown in FIG. 1;

FIG. 3 is a side elevational view of the sprocket shown in FIG. 1 with amodular belt engaged thereon;

FIG. 4 is a perspective view thereof;

FIG. 5 is another perspective view thereof;

FIG. 6 is an alternate embodiment of the sprocket of the presentinvention;

FIG. 7 is a side elevational view of another alternate embodiment of thepresent invention;

FIG. 8 is an end elevational view of the sprocket shown in FIG. 7;

FIG. 9 is a perspective view of the sprocket shown in FIG. 7 with a beltengaged thereon;

FIG. 10 is a side elevational view of another alternate embodiment ofthe present invention;

FIG. 11 is an end elevational view of the sprocket of FIG. 10;

FIG. 12 is a side elevational view of the sprocket of FIG. 11 with amodular belt engaged thereon;

FIG. 13 is perspective view thereof;

FIG. 14 is a schematic view of sprockets of the present invention incombination with a spraying system; and,

FIG. 15 is a side elevational view of another alternate embodiment ofthe present invention;

FIG. 16 is an end elevational view of the sprocket shown in FIG. 15;and,

FIG. 17 is a perspective view of the sprocket of FIG. 15 with a beltengaged thereon.

DETAILED DESCRIPTION OF THE INVENTION

Referring initially to FIG. 1, a drive sprocket 20 has a plurality ofsprocket teeth 23, 26 disposed in pairs 27 around the periphery of thesprocket 20. The sprocket 20 also has a central opening 29 that isformed in the shape of a square. The square shaped opening 29 is sizedto receive a square shaft 30 (FIG. 14) for rotating the sprocket 20 todrive a modular belt 32 (FIG. 3). The central opening 29 may be formedin other shapes to accommodate different shaft geometries as will beevident to those of ordinary skill in the art based on this disclosure.A large first opening 35 which may be oval-shaped as shown is formed inthe body of the sprocket 20. The first opening 35 is located betweenadjacent pairs 27 of teeth and is arranged such that it aligns with thehinge area of the module belt 32 when the belt 32 is engaged with thesprocket 20 as best shown in FIG. 3. As shown the teeth 23 are formed bya pair of side walls 38, 41 (opposite to wall 38); a pair of end walls44, 47; and a top wall 50. The teeth 26 are formed by a pair of sidewalls 53, 56 (opposite to wall 53); a pair of end walls 59, 62; and atop wall 65. The top walls 50 and 65 are angled relative to theirrespective side walls such that the top walls 50 and 65 are disposed inspaced apart relation and somewhat aligned with respect to their planartop surfaces. The sprocket 20 also has recessed curved portions 68extending from the end of the first openings 35 toward the center of thesprocket 20. The curved recessed portions 68 extend toward the teeth 23,26 and terminate at a shelf-like portion 71 between the respectiveteeth.

Turning to FIG. 2, the teeth 23, 26 are disposed in two rows along theperiphery of the drive sprocket 20. The teeth 23, 26 are offset alongthe circumference of the sprocket and are disposed on opposite sides ofa central axis 28 such that during driving of the modular belt 32 one ofthe teeth engages with one of the link ends 33 of the belt 32 andanother tooth engages with the transverse rib 34 on the belt 32. Theshelf portion 71 extends between adjacent teeth 23, 26 and is borderedon opposite sides by the curved recessed portions 68.

Turning to FIG. 3, the sprocket 20 is shown engaged with the modularbelt 32. The teeth 23, 26 engage with the link ends 33 and transverserib 34 of the respective belt modules 36. The teeth 23, 26 fit onopposite sides of the transverse rib 34 and provide tracking for thebelt 32. Also, the first openings 35 provide large openings and improvedaccess to the hinge areas for cleaning when the belt 32 passes over thedrive sprocket 20. The curved recessed portions 68 also provide roomnear the hinge and guide the cleaning fluid into the critical hingearea.

Turning to FIGS. 4 and 5, the end wall 47 of the tooth 23 may bedisposed at an angle such that the face of the tooth 23 reduces thecontact surface to the belt 32 and “squeezes” away residuals that maybecome trapped between the belt 32 and the sprocket 20.

In FIG. 6, an alternate embodiment of the sprocket 20 is shown. Sprocket60 has the same design for the teeth 23, 26 and the first openings 35and curved, recessed portions 68 but also includes openings 63 which arerelatively large and are positioned around the periphery of the centralshaft opening. The openings 63 may be desired to improve theaccessibility for water jets applied from the sides of the sprocket 60.This alternate design does not necessarily improve the cleaning of thehinge areas.

Turning to FIGS. 7-9, an alternate embodiment of the sprocket body thatis particularly suitable for molding is shown. Sprocket 80 has a centralopening 81 and has larger curved, recessed portions 83 that follow theoffset (with respect to the circumference as best shown in FIG. 8)arrangement of the sprocket teeth pairs 86, 89. The teeth are disposedin pairs 91 with each tooth on opposite sides of a central axis 94. Thecurved recessed portion 83 extends from the end wall 92 of one tooth 86to the end wall 95 of the next tooth 86 on the same side of the sprocket80. A first opening 98 formed between adjacent teeth 86, 89 provides anopening around the hinge area. The pairs 91 of sprocket teeth 86, 89provide for engagement of the transverse rib 34 and link end 33 of belt32 as shown in FIG. 9. The recessed portion 83 is disposed at an angle βwith respect to the radial axis 93. The angle β may be altered asnecessary to improve the flow of cleaning fluid.

Turning to FIGS. 10-13, an alternate embodiment of the sprocket isshown. Sprocket 110 has a central opening 114. Sprocket 110 increasesthe open space between the sprocket 110 and the hinge of the belt 32.The sprocket 110 may be used where tracking is not needed such as wherethe belt 32 is guided by guiding profiles on the edge of the belt 32. Asbest shown in FIG. 11, the sprocket 110 has a single row of teeth pairs113, 116 without any offset. Due to the wider teeth 113, 116 and theclosed V-shape of the space 118 between the teeth 113, 116, the sprocket110 contact area is larger and may negatively effect the cleaningproperties of the sprocket 110. The sprocket 110 also includes a curved,recessed portion 121. The recessed portion 121 extends to a firstopening 124 that aligns with the hinge area of belt 32 as shown in FIG.12.

FIG. 14 illustrates an arrangement of a spraying system include amanifold 150 with spray heads 153 arranged adjacent to sprockets 20 suchthat cleaning fluid 156 can be sprayed through the curved recessedportions 68 into the first openings 35 below the hinge areas of themodular belts 32 as they pass over the drive sprocket 20.

Turning to FIG. 15, another embodiment of the sprocket is shown. A drivesprocket 200 has a plurality of sprocket teeth 203, 206 disposed inpairs 207 around the periphery of the sprocket 200. The sprocket 200also has a central opening 209 that is formed in the shape of a square.The square shaped opening 209 is sized to receive a square shaft 30(FIG. 14) for rotating the sprocket 200 to drive a modular belt 32 asshown in FIG. 17. A plurality of first openings 215 are disposed aroundthe periphery of the sprocket 200 between the pairs 207. The firstopenings 215 extend inward toward the center of the sprocket 200 andterminate along a curved inner wall 218. A plurality of second openings221 are disposed between the first openings 215 and the central opening209. The second openings 221 may be desired to improve the accessibilityof water jets applied from the sides of the sprocket 200. Sprocket 200does not include recessed portions or grooves below the first opening215. The sprocket 200 is intended to have smooth surfaces with largeopenings to provide access to the hinge area of the belt and to alloweasier cleaning of the sprocket itself.

In FIG. 16, the teeth 203, 206 are disposed in two rows along theperiphery of the drive sprocket 200. The teeth 203, 206 are offset alongthe circumference of the sprocket 200 and are disposed on opposite sidesof a central axis 230. During driving of the modular belt 32 one of theteeth engages with one of the link ends 33 of the belt 32 and anothertooth engages with the transverse rib 34 on the belt 32. The transverserib 34 on the belt 32 fits in the space 238 between the teeth 203, 206.

Turning to FIG. 17, the sprocket 200 is shown engaged with the modularbelt 32. The teeth 203, 206 engage with the link ends 33 and transverserib 34 of the respective modules 36. The teeth 203, 206 fit on oppositesides of the transverse rib 34 and provide tracking for the belt 32.Also, the first openings 215 provide large openings and improved accessto the hinge areas for cleaning when the belt 32 passes over the drivesprocket 200. As indicated by arrow 250 the first openings 215 alignwith the hinge areas of the belt 32 as the belt 32 passes over thesprocket 200.

While the invention has been described in connection with certainembodiments, it is not intended to limit the scope of the invention tothe particular forms set forth, but, on the contrary, it is intended tocover such alternatives, modifications, and equivalents as may beincluded within the spirit and scope of the invention as defined by theappended claims.

1. A drive sprocket for driving a modular belt having a plurality of belt modules with intercalated link ends connected by transverse pivot members to form hinges, the belt modules having transverse ribs, the drive sprocket being driven by a shaft, the drive sprocket, comprising: a body having an opening in the center for receiving the shaft; the body having a plurality of teeth disposed in pairs along a periphery of the body, the body having at least one first opening formed between adjacent pairs of teeth, the first opening extending toward the center of the sprocket to provide access to the hinge area, when the belt engages with the sprocket, for application of cleaning fluid.
 2. The drive sprocket of claim 1, wherein the first opening in the body is disposed adjacent to a curved, recessed portion.
 3. The drive sprocket of claim 1, wherein each pair of teeth has a space therebetween sized to receive the transverse rib of the belt module when the belt is engaged with the sprocket.
 4. The drive sprocket of claim 1, wherein each pair of the teeth have walls that are facing and angled opposite each other.
 5. The drive sprocket of claim 1, wherein the teeth are disposed in pairs that are offset with respect to the circumference of the sprocket.
 6. The drive sprocket of claim 1, wherein the teeth are disposed in pairs with each tooth on opposite sides of a central axis.
 7. The drive sprocket of claim 1, wherein the teeth are disposed in a single row extending from a first side of the sprocket to the opposite side of the sprocket.
 8. The drive sprocket of claim 1, wherein the curved, recessed portion is oriented radially with respect to the sprocket.
 9. The drive sprocket of claim 1, further comprising at least one opening disposed between the central opening and the at least one first opening.
 10. The drive sprocket of claim 9, wherein the at least one opening comprises a plurality of openings disposed around the central opening.
 11. A drive sprocket, comprising: a body having a central opening, the body having a plurality of teeth disposed in pairs along a periphery of the body, the body having at least one first opening formed between adjacent pairs of teeth, the first opening extending toward the center of the sprocket.
 12. The drive sprocket of claim 11, wherein the first opening in the body is disposed adjacent to a curved, recessed portion.
 13. The drive sprocket of claim 11, wherein each pair of teeth has a space therebetween sized to receive the transverse rib of the belt module when the belt is engaged with the sprocket.
 14. The drive sprocket of claim 11, wherein each pair of the teeth have walls that are facing and angled opposite each other.
 15. The drive sprocket of claim 11, wherein the teeth are disposed in pairs that are offset with respect to a central axis.
 16. The drive sprocket of claim 11, wherein the teeth are disposed in a single row extending from a first side of the sprocket to the opposite side of the sprocket.
 17. The drive sprocket of claim 11, wherein the curved, recessed portion is oriented radially with respect to the sprocket.
 18. The drive sprocket of claim 11, further comprising at least one opening disposed between the central opening and the at least one first opening.
 19. The drive sprocket of claim 18, wherein the at least one opening comprises a plurality of openings disposed around the central opening.
 20. A system for cleaning a modular belt having a plurality of belt modules with intercalated link ends connected by transverse pivot members to form hinges, the belt modules having transverse ribs, the drive sprocket being driven by a shaft, the system comprising: a drive sprocket with a body having an opening in the center for receiving the shaft; the body having a plurality of teeth disposed in pairs along a periphery of the body, the body having at least one first opening formed between adjacent pairs of teeth, the first opening extending toward the center of the sprocket to provide access to the hinge area, when the belt engages with the sprocket, for application of cleaning fluid; a manifold disposed adjacent to a position where the sprocket engages with the belt; at least one spray head in fluid communication with the manifold for delivering a cleaning fluid to the hinge when the belt engages with the drive sprocket. 